Predictive, Sensor-Assisted Wireless Multimedia Systems

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ABSTRACT NCR-9725251 Stephen Wicker, Terrence Fine, and Joseph Halpern Cornell University Predictive, Sensor-Assisted Wireless Multimedia Systems The PCS systems of the future will provide a variety of services to mobile users, including voice, high speed data, video, e-mail, teleconferencing, and the transfer of medical Images. The intelligent PCS network will be required to provide channel access with a minimum of call blocking, negotiate quality of service, allocate resources, and track users throughout their sessions. It is proposed to develop a series of expert systems that will optimize random access, resource allocation, and mobility management protocols. These expert systems will use a number of technologies and techniques from the fields of neural networks, artificial intelligence, and knowledge representation. There are three levels of agents in the proposed intelligent PCS network: mobile user, Base Station Controller (BSC), and the Mobile Switching Center (MSC). It is assumed that the PCS system is cellular, with several BSC's interacting with a single MSC. It is proposed to determine a means for representing and exploiting the information available to each type of agent. At the physical layer, in-band transmitted power levels will be tracked by a grid of low-cost sensors (radiometers). The sensors will provide power measurements as a function of time and location. In the proposal it is shown that this information can be used in the development of a BSC-based intelligent ALOHA multiple access scheme. Neural networks are described that can efficiently use the sensor data to estimate the number of users involved in individual collision events. This information is used in turn to estimate the number of backlogged users and to select an optimal backoff algorithm, thus maximizing Aloha channel throughput. The sensor grid can also be used by the BSC and MSC to support resource allocation, handoffs, and the tracking of scheduled user transmissions. In the proposed research program, sensor-based expert systems will be developed for three distinct phases of PCS operation: system planning and layout, multiple access, and adaptive resource allocation. Higher level information can be acquired and used at the BSC's and the MSC. The BSC's will obtain information regarding the local users' bandwidth and quality of service requirements as a function of time. The BSC's will also track local channel conditions, and develop a detailed propagation model for the cell. The model will be used to as an aid to power control within the cell. The BSC is expected to act as an autonomous agent in local resource allocation and power control. The MSC will be responsible for allocating resources between cells. An allocation protocol will be developed to move resources between cells in response to traffic information acquired by the BSC's and passed to the MSC. The BSC's will also pass propagation and user tracking information to the MSC. The MSC will use this information to create a global propagation and user tracking model that will support the handoff decision process. An effort will be made to develop usage tendency profiles for individual users. The collection of user profiles will be used to develop models for global resource allocation.